Editing Variegation (section)

=== Pathological ===
[[Virus]] infections may cause patterning to appear on the leaf surface. The patterning is often characteristic of the infection. Examples are the ''mosaic viruses'', which produce a mosaic-type effect on the leaf surface or the [[citrus variegation virus]] (CVV). Recently{{when?|date=January 2017}} a virus disease, ''[[Hosta virus X]]'' (HVX) has been identified that causes mottled leaf coloring in [[hostas]]. At first, diseased plants were propagated and grown for their mottled foliage, at the risk of infecting other healthy hostas.<ref>{{cite web|title=Hosta Virus X|url=http://www.missouribotanicalgarden.org/gardens-gardening/your-garden/help-for-the-home-gardener/advice-tips-resources/pests-and-problems/diseases/viruses/hosta-virus-x.aspx|website=Missouri Botanical Garden|access-date=9 July 2016}}</ref> While these diseases are usually serious enough that the gardener would not grow affected plants, there are a few affected plants that can survive indefinitely, and are attractive enough to be grown for ornament; e.g. some variegated [[Abutilon]] varieties. [[Nutrient]] deficiency symptoms may cause a temporary or variable yellowing in specific zones on the leaf. [[Iron]] and [[magnesium]] deficiencies are common causes of this. [[Transposable element]]s can cause colour variegation.<ref>{{cite web|title=Barbara McClintock and the Discovery of Jumping Genes (Transposons)|url=http://www.nature.com/scitable/topicpage/barbara-mcclintock-and-the-discovery-of-jumping-34083#|website=Nature|access-date=9 July 2016}}</ref>